limited to black, white and grey is particularly notable in the composition of this painting. Picasso claimed that colour weakened the image and he therefore removed colour from his works in order to emphasise formal structure. His use of black and grey can be traced back to his Blue and Rose periods and continued through to these later depictions of war atrocities. Picasso's obsession with line and form and monochromatic values is reminiscent of Palaeolithic cave paintings and European drawing. This predominant use of black and grey also featured in the works of Spanish masters, like El Greco, José de Ribera, Francisco de Zurbarán, Diego Velázquez, and Francisco de Goya, which influenced Picasso's art. Picasso spent at least six months working on The Charnel House which has iconographic links to the graphic work of Picasso's Spanish compatriot Francisco de Goya (1746–1828). Picasso's friend and biographer Pierre Daix records that the title of the painting was not originally assigned to it by Picasso himself – the artist referred to The Charnel House as simply "my painting" or "the massacre"; nevertheless, in later years after the Second World War Picasso refused to retitle the painting once its identity as The Charnel House gained popularity, and it was first exhibited as such following Picasso's joining of the Communist Party of Spain in 1946. Significance and legacy William Rubin, curator at the Museum of Modern Art, said of the painting, "Its grisaille harmonies distantly echo the black and white of the newspaper images but, more crucially, establish the proper key for a requiem". Clement Greenberg for ArtForum opines that, "Charnel House is magnificently lyrical—and Picasso at his best is usually lyrical. And it is fitting that this picture should be lyrical, for it is an elegy, not an outcry or even a protest, and it is fitting that an elegy should chant rather than intone." Adrian Searle for The Guardian commented that, "It is a deceptively complex and rich painting, with an amazing tension between the subject and the language used to depict it – the slaughtered family heaped dead under a kitchen table, their bodies intertwined. The more you stare at it, the more you get entwined, too. In New York Magazine, Mark Stevens opined, "The Charnel House is yet another example of Picasso’s sublime intuition about how an artist must approach the century's horrors. Not long after he painted the picture, writers